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Still on the bottle

Why not consider a small reverse osmosis (RO) unit. For around £70 an RO unit will produce up to 50 gallons per day. Water free from pathogens and ionic constituents is guaranteed. As with many things initial outlay is higher than the few pounds for 5L of water but the carbon footprint per litre is a lot smaller on shipping alone. Also the RO unit takes up less space than the 5L bottle. The only problem with RO however is that many people do not like the taste of pure RO water as the chemicals present in spring water (from natural filtration and absorbtion) are now removed, these give the water some taste! Additionally a high level of waste bypass water is produced although this could be diverted to a container for garden water or even a grey water tank for use in toilet system. Obviously pre filters and RO membranes need replacing in RO units which have attached a carbon footprint but, if only used for drinking water, due to the size, weight production and shipping quantities of filters and membranes the footprint per litre I would guess is considerably less than 5 litres of water weighing 5 KG + the bottle weight. The main unit being made of steel and polyethylene should last a lifetime. Being of the Marine Fish Hobbyist type I regularly produce RO water in batches of 40 Litres taking about 6 hours to produce. The bypass water is then effectively used in plant tubs and baskets. The rest of the time the RO unit resides in the shed out of the way. At this rate filters and membranes should last me about two years. Fortunately I have good quality tasty scottish water that I can drink from the tap although if I lived in the calcium laden downs areas I'm sure the RO unit would be pressed into service for drinking water.

26 May 2011

2:24 pm